Impact of water renewal on the residual effect of larvicides in the control of Aedes aegypti

ABSTRACT

This study was carried out to evaluate the residual effect of three larvicides under laboratory conditions for 100 days in Aedes aegypti. The larval mortality rate was measured without water renewal or with daily water renewal (80 percent). With temephos, there was 100 percent mortality in both groups until the 70th day. In the Bacillus thuringiensis israelensis (Bti)-WDG test, there was no difference during the first 20 days. With Bti-G, without water renewal, mortality was sustained above 90 percent for up to 35 days. The second experiment (with water renewal) reduced the mortality to below 90 percent after the first 20 days. When renewed water was provided, the residual effect was significantly lower for all larvicides.